This is the 10764th most frequent Polish word.
dwudziestodwuletniego
"Of a twenty-two-year-old."
The word 'dwudziestodwuletniego' acts as an adjective in the genitive case, describing a masculine singular noun.
Widziałem dwudziestodwuletniego mężczyznę na ulicy.
I saw a twenty-two-year-old man on the street.
The word 'dwudziestodwuletni' is an adjective in the locative case, describing the noun 'student'.
Proszę opowiedzieć coś o tym dwudziestodwuletnim studencie.
Please tell something about this twenty-two-year-old student.
The word 'dwudziestodwuletniego' functions as an adjective in the accusative case, modifying the noun that it describes.